The VMC survey. XLV. Proper motion of the outer LMC and the impact of the SMC

Oliveira, Joana; Van Loon, Jacco

Abstract

Context. The Large Magellanic Cloud (LMC) is the most luminous satellite galaxy of the Milky Way and owing to its companion, the Small Magellanic Cloud (SMC), represents an excellent laboratory to study the interaction of dwarf galaxies.

Aims. The aim of this study is to investigate the kinematics of the outer regions of the LMC by using stellar proper motions to understand the impact of interactions, e.g. with the SMC about 250 Myr ago.

Methods. We calculate proper motions using multi-epoch Ks-band images from the VISTA survey of the Magellanic Clouds system (VMC). Observations span a time baseline of 2-5 yr. We combine the VMC data with data from the Gaia early Data Release 3 and introduce a new method to distinguish between Magellanic and Milky Way stars based on a machine learning algorithm. This new technique enables a larger and cleaner sample selection of fainter sources as it reaches below the red clump of the LMC.

Results. We investigate the impact of the SMC on the rotational field of the LMC and find hints of stripped SMC debris. The south east region of the LMC shows a slow rotational speed compared to the overall rotation. N-body simulations suggest that this could be caused by a fraction of stripped SMC stars, located in that particular region, that move opposite to the expected rotation.

Citation

Oliveira, J., & Van Loon, J. (2022). The VMC survey. XLV. Proper motion of the outer LMC and the impact of the SMC. Astronomy & Astrophysics, https://doi.org/10.1051/0004-6361/202142148

• Acceptance Date: Jan 20, 2022
• Publication Date: May 9, 2022
• Journal: Astronomy & Astrophysics
• Print ISSN: 0004-6361
• Publisher: EDP Sciences
• DOI: https://doi.org/10.1051/0004-6361/202142148
• Publisher URL: https://www.aanda.org/component/article?access=doi&doi=10.1051/0004-6361/202142148